JP2010105631A - Vehicular brake device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicular brake device capable of reducing the power consumption of an electric booster. <P>SOLUTION: The vehicular brake device 1 comprises an electric booster 3 for boosting the stepping force of a brake pedal 5 by driving an electric actuator 9, a wheel cylinder pressure control device 4 for controlling the pressure of a brake fluid to be fed from a master cylinder 10 to wheel cylinders 50-53 by the electric booster 3, and an electric actuator control means 11 for controlling the electric actuator so as to boost the stepping force of the brake pedal 5 at the predetermined boosting ratio. The electric actuator control means 11 changes the boosting ratio S of the electric booster during the control of the wheel cylinder pressure Pwc by the wheel cylinder pressure control device 4, and regulates the master cylinder pressure Pmc so as to be brought close to the wheel cylinder pressure Pwc regulated by the wheel cylinder pressure regulating means 4. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle brake device having an electric booster and a wheel cylinder pressure control device.

  2. Description of the Related Art Conventionally, a negative pressure type booster that boosts a pedaling force of a brake pedal by using an intake negative pressure of an engine is often used for a vehicle brake device such as an automobile. However, in recent years, vehicles such as electric vehicles and hybrid vehicles that cannot expect negative intake air pressure of an engine are becoming popular. Therefore, there is a demand for a negative pressure booster, and one of them is an electric booster described in Patent Document 1. This electric booster has a configuration that boosts the pedaling force of a brake pedal by using an actuator constituted by a motor, a ball screw, or the like.

JP 2007-191133 A

  However, since the electric booster obtains a brake boost by supplying an electric current to the motor and driving the actuator, the electric booster always consumes electric power according to the operation. For example, in a vehicle having an anti-lock brake system (hereinafter referred to as ABS) control device, when sudden braking is performed at a level at which the ABS control device operates, torque generated in the motor is larger than in normal braking. Therefore, a larger amount of current is required, and as a result, the power consumption of the electric booster increases.

  In order to efficiently use energy in accordance with such a situation where power consumption increases, it is necessary to reduce power consumption as much as possible. As a result of earnest research, the present inventor, in a vehicle brake device having a wheel cylinder pressure control device that adjusts the wheel cylinder pressure of each wheel such as ABS, has an electric booster during the control operation of the wheel cylinder pressure control device. I found out that there was a lot of waste in the power consumption of the device.

  Accordingly, the present invention provides a vehicle brake device that can reduce the power consumption of the electric booster during the control operation of the wheel cylinder pressure control device, which is one of the situations where the power consumption increases in the electric booster. The purpose is to do.

  In order to achieve the above-mentioned object, the invention of a vehicle brake device includes an electric booster that boosts the depressing force of a brake pedal by driving an electric actuator, and is supplied from a master cylinder to a wheel cylinder by the electric booster. A wheel cylinder pressure control device for controlling the wheel cylinder pressure of the brake fluid, and an electric actuator control means for controlling the electric actuator so as to boost the depression force of the brake pedal at a predetermined boost ratio, the electric actuator control means, It is characterized in that the control for changing the boost ratio is performed during the control of the wheel cylinder pressure by the wheel cylinder pressure control device.

  According to the present invention, the master cylinder pressure of the master cylinder is changed to the same pressure as the wheel cylinder pressure adjusted by the wheel cylinder pressure adjusting means by changing the boost ratio of the electric booster during the control of the wheel cylinder pressure. Thus, the driving force of the motor can be saved for generating a pressure exceeding the wheel cylinder pressure out of the master cylinder pressure generated according to the depression force of the brake pedal. Therefore, in a situation where the power consumption of the electric booster increases, the power consumption of the motor can be reduced by that amount, and the energy can be used efficiently.

Next, embodiments of the present invention will be described in detail below based on the drawings.
FIG. 1 is a diagram showing a configuration of a vehicle brake device 1 in the present embodiment, FIG. 2 is a diagram showing a configuration of a control unit of an electric booster 3, and FIG. 3 is a configuration of a control unit of an ABS control device 4. FIG.

  The vehicle brake device 1 shown in FIG. 1 basically generates a brake fluid pressure by the master cylinder 10 by boosting the pedal force of the brake pedal 5 by the electric booster 3, and the brake fluid pressure. Is transmitted to the wheel cylinders 50 to 53 of the wheel braking means provided on the front wheels 60 and 63 and the rear wheels 61 and 62 of the vehicle, and the rotation of the front wheels 60 and 63 and the rear wheels 61 and 62 is braked. It is intended to brake.

  The vehicle brake device 1 generates an electric booster 3 that boosts the depressing force of the brake pedal 5 by an electric actuator 9, and generates a master cylinder pressure that is a hydraulic pressure of the brake fluid according to an output from the electric booster 3. Disposed between the master cylinder 10 and the wheel cylinders 50 to 53, the master cylinder 10 to be driven, the wheel cylinders 50 to 53 driven according to the hydraulic pressure of the brake fluid supplied from the master cylinder 10, An ABS control device 4 (wheel cylinder pressure control device) that controls the hydraulic pressure of the brake fluid supplied from the master cylinder 10 to the wheel cylinders 50 to 53 is provided.

  The electric booster 3 includes an input rod 7 that reciprocates back and forth by operation of the brake pedal 5, a casing 8 that supports the input rod so as to reciprocate and is fixed to a bulkhead B that is a vehicle body member, and a casing 8. An electric actuator 9 is provided which is provided inside and boosts the depression force of the brake pedal 5 input from the input rod 7.

  A primary piston (not shown) is accommodated in the casing 8 so as to be reciprocally movable coaxially with the input rod 7, and is provided so as to be reciprocally movable back and forth by the electric actuator 9. The primary piston has a rear end connected to the input rod 7 and a front end facing the master cylinder 10.

  The electric actuator 9 includes a motor 6 that rotates when energized, and a ball feed screw (not shown) that converts the rotation of the motor 6 into linear motion, and the thrust of the primary piston according to the amount of current supplied to the motor 6. Can be changed.

  The master cylinder 10 is integrally attached to the electric booster 3, and has a configuration in which the brake fluid in the master cylinder 10 is pumped to the wheel cylinders 50 to 53 of the wheel braking means by the primary piston. Note that a general master cylinder 10 is used as it is, and since the configuration is known, a detailed description thereof will be omitted.

  A booster control unit (hereinafter referred to as booster C / U) 11 includes a control unit 102 having a CPU 109 and a motor drive circuit 111 for driving the motor 6. The control unit 102 includes a CPU 109, a ROM 110, a RAM 108, and I / O ports 107a and 107b.

  A stroke sensor 12 and a pressure sensor 103 for detecting the master cylinder pressure of the brake fluid in the master cylinder 10 are connected to the I / O port 107a. Moreover, you may connect various sensors, such as the temperature sensor 105 which detects the temperature of the motor 6 or C / U11 for boosters, and the voltage, the current sensor 106 as needed.

  The amount detected by each sensor is converted into a voltage or the like, for example, and input to the booster C / U 11. Input from each sensor is analog-digital converted by the CPU 109 mounted on the C / U 11 for the booster, and is acquired by the CPU 109 as a digital quantity.

  Further, the booster C / U 11 has a communication IC 113 in order to communicate with other C / Us installed in the vehicle. The ROM 110 in the control unit 102 stores a brake control program. The brake control program controls the motor drive circuit 111 in the booster C / U 11 and outputs it from the motor drive circuit 111. The motor 6 is driven to rotate in response to the generated signal, and the braking force is controlled by the electric actuator 9, thereby generating braking force on the wheels 60 to 63 and braking the vehicle.

  The electric booster 3 having the above configuration detects the operation amount of the brake pedal 5 by the stroke sensor 12 when the driver depresses the brake pedal 5 that is operated to generate braking force on the vehicle. A boost according to the detected amount is generated.

  The operation amount of the brake pedal 5 detected by the stroke sensor 12 is converted into an electric signal such as a voltage and is output to the booster C / U 11. The booster C / U 11 performs analog-to-digital conversion on the voltage output from the stroke sensor 12 by the CPU 109 mounted in the booster C / U 11 to obtain a digital quantity. The energization current to the motor 6 is controlled according to the amount.

  In the electric actuator 9, the motor 6 is rotated by energization, and is converted into a linear motion by a ball feed screw to generate thrust. The thrust of the electric actuator 9 changes corresponding to the amount of current to the motor 6.

  Accordingly, the position of the primary piston is controlled in accordance with the movement of the brake pedal 5 detected by the stroke sensor 12, and the master cylinder pressure is generated in the brake fluid in the master cylinder 10. At the same time, the input rod 7 is pushed toward the master cylinder 10 by the operation of the brake pedal 5.

  Accordingly, a master cylinder pressure is generated in the brake fluid in the master cylinder 10 by the primary piston and the input rod 7, and this master cylinder pressure is generated by the wheel cylinder 50 of the left front wheel 60, the wheel cylinder 51 of the right rear wheel 61, and the left rear wheel 62. The wheel cylinder 52 and the right front wheel 63 are transmitted to the wheel cylinder 53 and braking force is generated on the left front wheel 60, right rear wheel 61, left rear wheel 62, and right front wheel 63, and the vehicle can be braked.

  As shown in FIG. 1, the ABS control device 4 has a conventional general configuration, and includes a first system L1 for the left front wheel 60 and the right rear wheel 61, a left rear wheel 62, and a right front wheel 63. For this purpose, the second system L2 is provided.

  The first system L1 is connected to the master cylinder 10 via an oil passage L1a connected to the master cylinder 10 and a supply oil passage L1b branched from the oil passage L1a, and the left front wheel 60 via the supply oil passage L1c. Via an inlet valve 20 connected to the wheel cylinder 50, an outlet valve 30 connected to the wheel cylinder 50 of the left front wheel 60 via a discharge oil passage L1d, and a supply oil passage L1g branched from the oil passage L1a. Connected to the master cylinder 10 and connected to the wheel cylinder 51 of the right rear wheel 61 via the supply oil passage L1h and connected to the wheel cylinder 51 of the right rear wheel 61 via the discharge oil passage L1i. An outlet valve 31 is provided.

  The reservoir tank 13 is connected to the outlet valve 30 via the drain oil passage L1e and connected to the outlet valve 31 via the drain oil passage L1j, and is connected to the reservoir tank 13 via the recovery oil passage L1f. In addition, a recovery pump 16A connected to the oil passage L1a is included.

  The second system L2 is connected to the master cylinder 10 via an oil passage L2a connected to the master cylinder 10 and a supply oil passage L2b branched from the oil passage L2a, and is connected to the right front wheel 63 via a supply oil passage L2c. Via an inlet valve 23 connected to the wheel cylinder 53, an outlet valve 33 connected to the wheel cylinder 53 of the right front wheel 63 via a discharge oil passage L2d, and a supply oil passage L2g branched from the oil passage L2a. Connected to the master cylinder 10 and connected to the wheel cylinder 52 of the left rear wheel 62 through the supply oil passage L2h and connected to the wheel cylinder 52 of the left rear wheel 62 through the discharge oil passage L2i. Including an outlet valve 32.

  The reservoir tank 13 is connected to the outlet valve 32 via the drain oil passage L2e and connected to the outlet valve 32 via the drain oil passage L2j, and is connected to the reservoir tank 13 via the recovery oil passage L2f. In addition, a recovery pump 16B connected to the oil passage L2a is included.

  The collection pumps 16 </ b> A and 16 </ b> B are driven by a pump motor 17. The oil passages L1a and L2a are provided with accumulators 80 and 81 that alleviate fluid pressure fluctuations in the master cylinder.

  A control unit 209 having a CPU 207, a left front wheel 60, a right rear wheel 61, a left rear wheel 62, and a right front wheel 63 are included in an ABS control device control unit (hereinafter referred to as ABS control device C / U) 19. There is a drive circuit 214 for opening and closing the inlet valves 20 to 23 for each wheel and a drive circuit 215 for opening and closing the outlet valves 30 to 33.

  The control unit 209 includes a CPU 207, ROM 208, RAM 206, and I / O port 205. The I / O port 205a is connected to a pressure sensor 103 and wheel speed sensors 40 to 43 that detect wheel speeds that are rotational speeds of the wheels 60 to 63.

  Each sensor converts the detection amount into a voltage or the like and outputs it. The output from each sensor is input to the I / O port 205a, converted from analog to digital by the CPU 207 mounted on the ABS control device C / U 19, and acquired as a digital quantity by the CPU 207. The ABS control device C / U 19 has a communication IC 213 for communicating with the booster C / U 11 installed in the vehicle and other C / Us.

  The ABS controller C / U 19 monitors the output signals from the wheel speed sensors 40 to 43, calculates the vehicle body speed from the output signals of the wheel speed sensors 40 to 43, and determines the slip ratios of the wheels 60 to 63, respectively. calculate. And when the slip ratio of any one or a plurality of wheels among the wheels 60 to 63 becomes a value higher than a preset threshold value, it is determined that the lock has occurred, and the value until the lock is released Control is performed to reduce the wheel cylinder pressure Pwc of the locked wheels (60 ...).

  When the wheel (60...) Is unlocked by the pressure reduction control of the wheel cylinder pressure Pwc, the wheel cylinder pressure Pwc of the wheel (60...) Is increased again. When the wheel (60...) Is locked again by increasing the wheel cylinder pressure Pwc, control is performed to reduce the wheel cylinder pressure Pwc, and these operations are repeated.

  When the wheel cylinder pressure Pwc is reduced in the ABS control device 4, the inlet valve (20 ...) of the locked wheel (60 ...) is closed and the outlet valve (30 ...) of the locked wheel (60 ...) is opened. The wheel cylinder pressure Pwc applied to the wheels (60...) Is reduced by moving the brake fluid to the reservoir 13.

  Here, the brake fluid moved to the reservoir 13 is returned to the electric booster 3 by the pump motor 17 and the recovery pumps 16A and 16B. When the ABS control unit C / U 19 determines that the wheels (60...) Are unlocked, the inlet cylinder (20...) Is opened and the outlet valve (30. ) Generates a wheel cylinder pressure Pwc that is the same pressure as the master cylinder pressure Pmc generated in the master cylinder 10.

  Next, operation | movement of the vehicle brake device 1 which has the said structure, and its effect are demonstrated below using FIGS. 4 to 7 are flowcharts for explaining the operation of the vehicle brake device 1. FIG. 8 is a master cylinder pressure Pmc, wheel cylinder pressure Pwc, pedal depression force F, boost ratio S, and a specific wheel at the time of brake control. It is a graph which shows typically the relation of wheel speed V. In FIG. 4 to FIG. 7, “A” indicates the operation of the ABS control device 4, and “double” indicates the operation of the electric booster 3.

  First, as shown in FIG. 4, in S201, the ABS controller C / U 19 detects the wheel speeds of the wheels 60 to 64 detected by the wheel speed sensors 40 to 43 of the wheels 60 to 63 and the master cylinder pressure. The wheel cylinder pressure Pwc of each wheel estimated from the signal of the pressure sensor 13 and the wheel speed of each wheel is constantly monitored. And in order to judge wheel lock, the wheel speed of each wheel 60-63 and a vehicle body speed are always compared in S202.

  Then, as shown in FIG. 5, in step S301, the booster C / U 11 monitors the value of the stroke sensor 12, and in step S302, the ABS operation flag output from the ABS controller C / U 19 is monitored. To start.

  As shown in FIG. 6, when the booster C / U 11 detects the depression of the brake pedal 5 by the process of S301 in S401, the boost control corresponding to the depression force F of the brake pedal 5 is performed in S402. The booster C / U 11 drives the motor 6 of the electric actuator 9 to boost the depression force F of the brake pedal 5 at a constant boost ratio S (corresponding to electric actuator control means). Accordingly, as shown in (1) of FIG. 8, as the pedal force F is increased at a constant rate, the master cylinder pressure Pmc is also increased at a constant rate.

  Then, in S403, it is determined by the ABS control device C / U 19 whether at least one of the wheels 60 to 63 is locked. The ABS control device C / U 19 calculates the slip ratios of the wheels 60 to 63 based on the values of the wheel speed sensors 40 to 43 of the wheels 60 to 63 and the vehicle body speed monitored in S201, respectively. Determines that the wheel (60...) That has exceeded the preset threshold value is locked (see (2) in FIG. 8), and executes the following ABS control.

  In S <b> 404, ABS control is started by the ABS control device C / U 19, and an ABS operation flag high is transmitted to the electric booster 3. In S405, a process of releasing the lock by reducing the wheel cylinder pressure Pwc of the locked wheel (60...) Is performed. The ABS controller C / U 19 controls the inlet valve driving circuit 214 and the outlet valve driving circuit 215 to close the inlet valve (20...) Of the locked wheel (60...) And to close the outlet valve (30...). Open and reduce the wheel cylinder pressure Pwc of the locked wheel (60...).

  And in S406, the boost suppression process which changes the boost ratio S of the electric booster 3 and suppresses a boost is performed. The boost suppression process is not executed when the road surface condition is unstable. For example, as shown in FIG. 7, the slip ratio is always calculated in S501, a difference is taken compared with the value of the slip ratio at the start of locking, and when the difference is equal to or greater than a preset threshold value (step S501). YES), the boost suppression process is stopped because the road surface condition is unstable. When performing the processing of S501, the electric booster 3 continues normal boost control.

  If the difference between the slip ratios is within a preset threshold value (in the case of NO in step S501), the ABS controller C / U 19 is the largest of the wheel cylinder pressures Pwc of the wheels 60 to 63 in step S502. A value of a high wheel cylinder pressure Pwcmax is selected and transmitted to the booster C / U11.

  In step S503, when the booster C / U 11 receives the pressure reduction start signal and the value of the wheel cylinder pressure Pwcmax from the ABS control device C / U 19, the motor 6 of the electric actuator 9 is driven and controlled. A process of lowering the boost ratio S is performed, and the master cylinder pressure Pmc is adjusted so as to approach the value of the wheel cylinder pressure Pwcmax as shown in (3) of FIG.

  As described above, there is a possibility that the stroke of the brake pedal 5 may fluctuate by performing the control to change the boost ratio S to the lower side. However, the accumulator is provided between the master cylinder 10 and the ABS control device 4. Since 80 and 81 are interposed, the fluid pressure fluctuation in the master cylinder 10 can be reduced, and the fluctuation of the stroke of the brake pedal 5 can be suppressed.

  After the boost suppression processing in steps S501 to S504 is completed, the ABS control device C / U 19 determines whether or not the wheels (60...) Are unlocked in S407. At this time, if the wheel (60...) Is not unlocked (NO in step S407), the process proceeds to boost suppression control in step S406.

  On the other hand, if the wheels (60...) Are unlocked (YES in step S407), the ABS controller C / U 19 controls the inlet valve driving circuit 214 and the outlet valve driving circuit 215 in step S408. Open the inlet valve (20 ...) of the unlocked wheel (60 ...), close the outlet valve (30 ...), and increase the wheel cylinder pressure Pwc.

  After the wheel cylinder pressure Pwc is increased, the ABS controller C / U 19 again determines whether or not at least one of the wheels 60 to 63 is locked in S409. If a lock is detected again (YES in step S409), the process proceeds to a boost suppression process in S406. On the other hand, if no lock is detected (NO in step S409), the ABS operation is canceled and the ABS operation flag is set to low. The booster C / U 11 performs normal boost control.

  The situation in which the ABS control device 4 operates can be broadly classified as follows: 1. When braking suddenly Two scenes are assumed, such as braking when the friction coefficient of the road surface is low. 1. At the time of sudden braking, it is assumed that the driver depresses the brake pedal 5 with a strong force, and a large boost is generated even for a short time, so that a large current is supplied to the motor 6 accordingly. The power consumption of the electric booster 3 also increases.

  In addition, 2. When the friction coefficient of the road surface is low, the braking distance becomes longer than that when braking on a normal road surface, and accordingly, the time for the driver to step on the brake pedal 5 becomes longer and doubles accordingly. Since the time for generating the force becomes longer, as a result, the current continues to be supplied to the motor 6, and the power consumption of the electric booster 3 increases.

  While the ABS control device 4 is operating, the electric booster 3 continues to generate a boost according to the output voltage from the stroke sensor 12. However, when the master cylinder pressure Pmc generated by the electric booster 3 results in a wheel cylinder pressure Pwc that exceeds one of the wheel cylinder pressures Pwc to be applied to the wheels 60 to 63, or more than one wheel is locked. Since the ABS control device 4 is in operation, the wheel cylinder pressure Pwc exceeding the lock of the wheel 60 is reduced by the operation of the ABS control device 4.

  For this reason, the electric booster 3 generates more boost than necessary for the pressure reduced by the ABS control device 4, and accordingly, the electric booster 3 consumes more power than necessary. Will be.

  Therefore, by the above-described boost suppression process, during the ABS operation, the motor 6 of the electric actuator 9 is driven and controlled to reduce the boost ratio S, and the master cylinder pressure Pmc is the same as the value of the wheel cylinder pressure Pwcmax. The motor 6 is driven to generate a pressure exceeding the wheel cylinder pressure Pwc among the master cylinder pressure Pmc generated according to the depression amount of the brake pedal 5 in the electric booster 3 The power can be saved and the power consumption of the motor 6 can be reduced. Therefore, energy can be used efficiently and power saving can be achieved.

  Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

The figure which shows the structure of the brake device for vehicles in this Embodiment. The figure which shows the structure of the control unit of an electric booster. The figure which shows the structure of the control unit of an ABS control apparatus. The flowchart explaining the processing content of C / U for ABS control apparatuses. The flowchart explaining the processing content of C / U for boosters. The flowchart explaining a brake control method. The flowchart explaining the content of a boost suppression process. The graph which shows typically the relation of master cylinder pressure at the time of brake control, wheel cylinder pressure, pedal effort, boost ratio, and wheel speed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle brake device 3 Electric booster 4 ABS control device (wheel cylinder pressure control device)
5 Brake pedal 6 Motor 9 Electric actuator 10 Master cylinder 11 Booster C / U (electric actuator control means)
12 Stroke sensors 16A, 16B Pump 17 Pump motor 19 ABS control device C / U
20 Left front wheel inlet valve 21 Right rear wheel inlet valve 22 Left rear wheel inlet valve 23 Right front wheel inlet valve 30 Left front wheel outlet valve 31 Right rear wheel outlet valve 32 Left rear wheel outlet valve 33 Right front wheel outlet valve 40 Left front wheel wheel speed wheel Cylinder 41 Right rear wheel wheel speed wheel cylinder 42 Left rear wheel wheel speed wheel cylinder 43 Right front wheel wheel speed wheel cylinder 50 Left front wheel brake 51 Right rear wheel brake 52 Left rear wheel brake 53 Right front wheel brake 60 Left front wheel 61 Right rear wheel 62 Left rear wheel 63 Right front wheel 80 Accumulator 81 Accumulator 90 Communication bus 102 Control unit,
105 Temperature sensor 106 Voltage / current sensor 107a, 107b I / O port 108 RAM
109 CPU
110 ROM,
111 Motor drive circuit 113 Communication IC
205a, 205b I / O port 206 RAM
207 CPU
208 ROM
209 Control unit 213 Communication IC
214 Inlet valve drive circuit 215 Outlet valve drive circuit Pmc Master cylinder pressure Pwc Wheel cylinder pressure F Pedal depression force V Wheel speed S Boost ratio

Claims (5)

An electric booster that boosts the pedaling force of the brake pedal by driving an electric actuator;
A wheel cylinder pressure control device for controlling the wheel cylinder pressure of the brake fluid supplied from the master cylinder to the wheel cylinder by the electric booster;
Electric actuator control means for controlling the electric actuator so as to boost the depression force of the brake pedal at a predetermined boost ratio;
The electric actuator control means performs control to change the boost ratio during control of wheel cylinder pressure by the wheel cylinder pressure control device. The electric actuator control means includes
The boost ratio is changed so that the master cylinder pressure set according to the depression amount of the brake pedal by the electric booster approaches the wheel cylinder pressure controlled by the wheel cylinder pressure control device. The vehicle brake device according to claim 1. The wheel cylinders are respectively provided on a plurality of wheels;
The said electric actuator control means changes the said boost ratio so that the said master cylinder pressure may approximate the wheel cylinder pressure with the highest pressure among the wheel cylinder pressures of each said wheel cylinder. The brake device for vehicles as described.   The wheel cylinder pressure control device has a slip ratio calculating means for calculating a slip ratio of a wheel provided with the wheel cylinder, and the slip ratio calculated by the slip ratio calculating means is higher than a preset threshold value. The vehicle brake device according to any one of claims 1 to 3, wherein the wheel cylinder pressure is controlled. The electric actuator control means includes
5. The vehicle brake device according to claim 4, wherein when the slip ratio changes by a predetermined value or more from the start of the control of the wheel cylinder pressure, the control for changing the boost ratio is stopped.

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